Which extraembryonic membrane in humans prevents desiccation of the embryo inside the uterus?
Chorion
Allantois
Yolk sac
Yolk sac
D.
Yolk sac
Amnion is an extraembryonic membrane that surrounds embryo in reptiles, birds and mammals. It provides a kind of private aquarium to the embryo and protects it from mechanical shock and desiccation.
Chorion (serosa) is the outermost extraembryonic membrane in reptiles, birds and mammals. It surrounds the whole embryonic system of the embryo.
Yolk sac contains yolk in reptiles and birds. In mammals yolk, the sac is also known as a umnillical vesicle. It is connected to enter on of the embryo by a slender yolk stalk.
Allantois functions as an embryonic urinary bladder or as a respiratory extension of a handgun in reptiles and birds. In mammals, it is modified to carry blood vessel to and from the placenta.
Seminal plasma in human is rich in
fructose, calcium and certain enzymes
fructose and calcium but has no enzymes
glucose and certain enzymes but has no calcium
glucose and certain enzymes but has no calcium
The correct sequence of spermatogenetic stages leading to the formation of sperms in mature human testis is
spermatocyte-spermatoogonia-spermatid-sperms
spermatogonia-spermatocyte-spermatid
spermatid-spermatocyte-spermatogonia-sperms,
spermatid-spermatocyte-spermatogonia-sperms,
In human adult females, oxytocin
is secreted by the anterior pituitary
stimulates the growth of mammary glands
stimulates pituitary to secrete vasopressin
stimulates pituitary to secrete vasopressin
In humans, at the end of the first meiotic division, the male germ cells differentiate into the
Primary spermatocytes
Secondary spermatocytes
spermatids
spermatids
